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regular busy vs fast busy
- Thread starter bharley
- Start date
What kind of documentation? I can give you references to the actual tones and the official "designation" though Lundah's reply pretty much says it all.
I would only add that "switch congestion" would also be reported as a fast busy which is exactly consistant with his/her definition.
Of course on ISDN you get a cause code down the D chanel that gives much more precise diagnostics than in-band tones, so if you are using a PRI you can learn a lot (not only the cause code but who is sending it).
If you are not on ISDN if you have access to a device on ISDN that can log the cause codes you can place a call to a non-ISDN line and still get the cause info.
Why are you asking?
I would only add that "switch congestion" would also be reported as a fast busy which is exactly consistant with his/her definition.
Of course on ISDN you get a cause code down the D chanel that gives much more precise diagnostics than in-band tones, so if you are using a PRI you can learn a lot (not only the cause code but who is sending it).
If you are not on ISDN if you have access to a device on ISDN that can log the cause codes you can place a call to a non-ISDN line and still get the cause info.
Why are you asking?
I always understood that a 'fast busy' indicated a busy from one central office switch to another central office switch. A slow busy indicates the person that you are trying to call is on the phone.
A goggle search appears to agree for the most part.
I couldn't find anything from a LEC that actually said that though.
A goggle search appears to agree for the most part.
I couldn't find anything from a LEC that actually said that though.
A general rule-of-thumb that works for me is:
Fast busy means trouble in the telco cloud... call your carrier.
Slow busy means call cannot be delivered to terminating equipment... check terminating equipment then ask carrier to check local loop to equipment premise.
WinN
Fast busy means trouble in the telco cloud... call your carrier.
Slow busy means call cannot be delivered to terminating equipment... check terminating equipment then ask carrier to check local loop to equipment premise.
WinN
According to Bellcore TR-TSY-000064 LSSGR (Lec Switching System Generic Requirements), they are described as
"Line Busy" - 480 + 620 Hz 0.5 sec on, 0.5 sec off, repeating.
"Reorder" - 480 + 620 Hz 0.25 sec on, 0.25 sec off repeating.
RUS Bulletin 1753E-001 (USDA Rural Utilities Service) Specification for Digital, Stored Program Controlled Central Office Equipment says:
9.2.4 Reorder, all paths busy, and no circuit tone shall be... (see bove for actual specs)
TiA/EIA-467B (the TIA/EIA spec covering PBXes) calls them "Busy Tone" and "Reorder tone", respectively. Here are the definitions from there:
6.3.4.1.3 Busy tone, sometimes referred to as slow-busy tone, is applied toward the caller as an indication that the called station line or all lines in a called line hunting group are busy. This signal is normally held applied as long as the caller remains off-hook. In some instances on calls originated by a local PBX caller, a PBX may disconnect the signal approximately 30 seconds after the caller has been connected to Busy tone. On incoming calls from the public network or other switching systems, the PBX shall not disconnect the signal until it receives a disconnect indication from the caller.
6.3.4.1.2 Reorder tone is variously referred to as paths-busy tone, all-trunks-busy tone and fast busy tone. This signal is applied toward the caller when call blockage is encountered due to unavailability of equipment or channels. This signal shall be held applied as long as the caller remaions off-hook. On calls originated by a local PBX caller, in some instances, a PBX may disconnnect the signal approximately 30 seconds after the caller has been connected to Reorder tone. On incoming calls from the public network or other switching systems, the PBX shall not disconnect the signal until it receives a disconnect indication from the caller.
Note that this applies to both blockage due to unavailability of _equipment_ as well as _channels_ (e.g. trunks). Therefore, according to my reading, it could be returned by a (non non-blocking) PBX where the matrix was full even if trunks were available.
In the ISDN world there are quite a few causes that translate to either Busy or fast busy (the tone to be applied is covered seperate for mthe cause code so I cannot summarize, but it is likely that all but cause 17 would return Reorder tone):
Cause 17 = Busy (user busy)
Cause 34 = No circuit available
Cause 38 = Network out of order (relatively long term problem)
Cause 41 = Network problem , redial (short term problem)
Cause 42 = Network busy, redial (Switching Equipment Congestion)
Cause 47 = Resource unavailable (used if none of the above applies)
There are also a class of causes that apply to "Service or option not available" that might also return a Reorder tone:
Cause 50 = Requested facility not subscribed
Cause 52 = Outgoing calls barred
Cause 54 = Incoming calls barred
Cause 57 = Bearer capability not authorized
Cause 58 = Bearer service not presently available
Now you can se why I suggest that when troubleshooting using an ISDN line to place or receive the call. Not only do you get a cause code but you get and indication of who sent it:
First Octet of cause code:
80 = User
81 = private network serving the local user (e.g. local PBX)
82 = public network serving the local user (e.g. local CO)
83 = transit network
84 = public network serving the remote user (e.g. far end CO)
85 = private network serving the remote user (e.g. far end PBX)
87 = international network
8A = network beyond interworking point (e.g. far end non-ISDN network such as POTS or Switched 56)
A lot more detail than simply brrp-brrp-brrp-brrp or brrrrrp ---brrrrrp---brrrrrrp---brrrrrp....
I hope this helps. It would be useful to know why you are asking.
"Line Busy" - 480 + 620 Hz 0.5 sec on, 0.5 sec off, repeating.
"Reorder" - 480 + 620 Hz 0.25 sec on, 0.25 sec off repeating.
RUS Bulletin 1753E-001 (USDA Rural Utilities Service) Specification for Digital, Stored Program Controlled Central Office Equipment says:
9.2.4 Reorder, all paths busy, and no circuit tone shall be... (see bove for actual specs)
TiA/EIA-467B (the TIA/EIA spec covering PBXes) calls them "Busy Tone" and "Reorder tone", respectively. Here are the definitions from there:
6.3.4.1.3 Busy tone, sometimes referred to as slow-busy tone, is applied toward the caller as an indication that the called station line or all lines in a called line hunting group are busy. This signal is normally held applied as long as the caller remains off-hook. In some instances on calls originated by a local PBX caller, a PBX may disconnect the signal approximately 30 seconds after the caller has been connected to Busy tone. On incoming calls from the public network or other switching systems, the PBX shall not disconnect the signal until it receives a disconnect indication from the caller.
6.3.4.1.2 Reorder tone is variously referred to as paths-busy tone, all-trunks-busy tone and fast busy tone. This signal is applied toward the caller when call blockage is encountered due to unavailability of equipment or channels. This signal shall be held applied as long as the caller remaions off-hook. On calls originated by a local PBX caller, in some instances, a PBX may disconnnect the signal approximately 30 seconds after the caller has been connected to Reorder tone. On incoming calls from the public network or other switching systems, the PBX shall not disconnect the signal until it receives a disconnect indication from the caller.
Note that this applies to both blockage due to unavailability of _equipment_ as well as _channels_ (e.g. trunks). Therefore, according to my reading, it could be returned by a (non non-blocking) PBX where the matrix was full even if trunks were available.
In the ISDN world there are quite a few causes that translate to either Busy or fast busy (the tone to be applied is covered seperate for mthe cause code so I cannot summarize, but it is likely that all but cause 17 would return Reorder tone):
Cause 17 = Busy (user busy)
Cause 34 = No circuit available
Cause 38 = Network out of order (relatively long term problem)
Cause 41 = Network problem , redial (short term problem)
Cause 42 = Network busy, redial (Switching Equipment Congestion)
Cause 47 = Resource unavailable (used if none of the above applies)
There are also a class of causes that apply to "Service or option not available" that might also return a Reorder tone:
Cause 50 = Requested facility not subscribed
Cause 52 = Outgoing calls barred
Cause 54 = Incoming calls barred
Cause 57 = Bearer capability not authorized
Cause 58 = Bearer service not presently available
Now you can se why I suggest that when troubleshooting using an ISDN line to place or receive the call. Not only do you get a cause code but you get and indication of who sent it:
First Octet of cause code:
80 = User
81 = private network serving the local user (e.g. local PBX)
82 = public network serving the local user (e.g. local CO)
83 = transit network
84 = public network serving the remote user (e.g. far end CO)
85 = private network serving the remote user (e.g. far end PBX)
87 = international network
8A = network beyond interworking point (e.g. far end non-ISDN network such as POTS or Switched 56)
A lot more detail than simply brrp-brrp-brrp-brrp or brrrrrp ---brrrrrp---brrrrrrp---brrrrrp....
I hope this helps. It would be useful to know why you are asking.
Well the concept is the same, and it IS useful for the PBX user to be able to distinguish if the Reorder is local or not. So, I guess that adds up.
Hard to find this stuff online. My employer makes telephone equipment, so we have collected quite a bit of info over the years. I wish we had the entire LSSGR but we only
have a few sections.
I also belong to a group of telephone collectors, and some of these guys get weird lots of stuff (out of dumpsters?) so I have bought some very nice "inside" stuff (T1 training course, Craft handbnooks, etc) via that route.
The European standards are now downloadable on a "limited personal" basis.
The RUS stuff is available online as well. Unfortunately, a lot of the more detailed stuff references ITU and/or Bellcore/Telcordia specs, so it is sort of disapointing. Also the PDF's do not include any of the illustrations.
The US and ITU stuff is hard to come by. There was a site that had ITU stuff for a while, but they are no longer there.
While we don't have everything, we have the important ISDN stuff. It is great fun to have the specs to wave in front of the Telco if it is there thought. More often it is a PBX vendor that is non-compliant. It is fun to wave the specs in front of their noses too.
Of course if the problem is ours, we fix it.
For one of the most complete lists of ISDN cause codes (compiled by yours truly from a variety of sources) see:
(Scroll down to "ISDN and Telco resources", in the right column)
I am still wondering why bharley was asking. Hopefully we've answered his question by now
have fun
Hard to find this stuff online. My employer makes telephone equipment, so we have collected quite a bit of info over the years. I wish we had the entire LSSGR but we only
have a few sections.
I also belong to a group of telephone collectors, and some of these guys get weird lots of stuff (out of dumpsters?) so I have bought some very nice "inside" stuff (T1 training course, Craft handbnooks, etc) via that route.
The European standards are now downloadable on a "limited personal" basis.
The RUS stuff is available online as well. Unfortunately, a lot of the more detailed stuff references ITU and/or Bellcore/Telcordia specs, so it is sort of disapointing. Also the PDF's do not include any of the illustrations.
The US and ITU stuff is hard to come by. There was a site that had ITU stuff for a while, but they are no longer there.
While we don't have everything, we have the important ISDN stuff. It is great fun to have the specs to wave in front of the Telco if it is there thought. More often it is a PBX vendor that is non-compliant. It is fun to wave the specs in front of their noses too.
Of course if the problem is ours, we fix it.
For one of the most complete lists of ISDN cause codes (compiled by yours truly from a variety of sources) see:
(Scroll down to "ISDN and Telco resources", in the right column)
I am still wondering why bharley was asking. Hopefully we've answered his question by now
have fun
- Thread starter
- #9
Wow...you guys rock. Thanks so much..this is helpful. The situation I have is our call center business managers do not understand this stuff; so I need to give them documentation as to what the tones mean.
In one situation, our outbounding dialing staff received a "fast-busy" after they dialed; however an hour or two later the call would be completed to the same #.
After using some leverage our company has with the Nortel design team I ran this question by them in which they said that "fast-busy" means that the call could not reach the destination via the PSTN network. So anotherwords, the path that the call needed to take got cut off or couldn't find its final destination.
So with that I was wondering what other information would be out there to help define these items.
I appreciate all the feedback. Thanks.
In one situation, our outbounding dialing staff received a "fast-busy" after they dialed; however an hour or two later the call would be completed to the same #.
After using some leverage our company has with the Nortel design team I ran this question by them in which they said that "fast-busy" means that the call could not reach the destination via the PSTN network. So anotherwords, the path that the call needed to take got cut off or couldn't find its final destination.
So with that I was wondering what other information would be out there to help define these items.
I appreciate all the feedback. Thanks.
Blocking" or the general inability to complete a call is a basic cahracterisitc of a circuit switched network such as the PSTN.
If you are able to complete a call you get a private path that is your alone.
This is in stark contrast to packet technology such as VOIP. There there are shared data paths and in some cases a call can degrade for a period of time due to lack of capacity.
Therefore, during the busiest hour of the day it is normal for there to be some cases of all trunks busy. This is the nature o fth ebeast - to put in enough paths that this would NEVER happens would not be practicle since these extra paths would be idle most of the time.
For the purposes of your managers they should consider the fast busy to mean "all circuits are busy - please try your call again later".
Diaaling 2 or 3 times immeidatley may work, since talk paths are constantly being built up and torn down. SO even in the cases where a given portion of the network is very busy there is still some chance you might get through.
Now, if this happens frequently then you may want to try and track this down further. The first place to start would be to see if using a 101XXXX prefix causes the call to go through if so you can complain to your LD carrier.
If this makes no difference then there may be nothing you can do easily.
Good luck
If you are able to complete a call you get a private path that is your alone.
This is in stark contrast to packet technology such as VOIP. There there are shared data paths and in some cases a call can degrade for a period of time due to lack of capacity.
Therefore, during the busiest hour of the day it is normal for there to be some cases of all trunks busy. This is the nature o fth ebeast - to put in enough paths that this would NEVER happens would not be practicle since these extra paths would be idle most of the time.
For the purposes of your managers they should consider the fast busy to mean "all circuits are busy - please try your call again later".
Diaaling 2 or 3 times immeidatley may work, since talk paths are constantly being built up and torn down. SO even in the cases where a given portion of the network is very busy there is still some chance you might get through.
Now, if this happens frequently then you may want to try and track this down further. The first place to start would be to see if using a 101XXXX prefix causes the call to go through if so you can complain to your LD carrier.
If this makes no difference then there may be nothing you can do easily.
Good luck
jon24422531
Technical User
ISDNman, sorry to ask, but what do you mean by 'using a 101XXX prefix'.
Jonathan Schofield
Jonathan Schofield
The 101XXXX code is used when you want to select a specific LD carrier when placing a call or when the line has no PIC programmed on it from the service provider. This is sometimes called 'dial-around'. Also handy when a carrier has facility trouble completing calls. You can use a different one to get your call thru....
This was put into service during the early days of equal access back in the mid 80s. At that time the codes were 10XXX, but because of growth in the industry it was expanded in the 90s (1995-96 time) to 7 digits 101XXX. The XXXX part is the CIC code assigned to the IXC carriers by NANPA. You can get a list of them from the NANPA web site (nanpa.com)
Hope this helps!
....JIM....
This was put into service during the early days of equal access back in the mid 80s. At that time the codes were 10XXX, but because of growth in the industry it was expanded in the 90s (1995-96 time) to 7 digits 101XXX. The XXXX part is the CIC code assigned to the IXC carriers by NANPA. You can get a list of them from the NANPA web site (nanpa.com)
Hope this helps!
....JIM....
Right! Really good for troubleshooting and for really urgent calls.
If you consistently have problems reaching certain areas with your "PIC" (Presubscribed Interexchange Carrier) and dial around with another carrier works (at the time the proble is occurring), then you can call your PIC and demand they take care of it since you know the problem is theirs.
Unlike the orginal intent to allow easy acess to different carriers, most carriers charge a premium for dial around users, so it shouldn't be used as a substitute for demanding a carrier fix problems (assuming they are long standing problems).
Three that are worth trying for troubleshooting are:
1010222 = MCI (original MCI network, not the Worldcom net)
1010333 = Sprint
1010288 = AT&T
You would dial 101XXXX 1 + 10 digits or for international:
101XXXX 011 + country code + number.
If you get the same result with all three then it isn't the LD carrier.
On the other hand, there is a class of carriers that ONLY offer accesss through manual dial around (for example 1010321.
To verify your current PIC, dial 1 700-555-4141 and listen for an announcment (e.g "thank you for choosing xyz").
Good luck.
If you consistently have problems reaching certain areas with your "PIC" (Presubscribed Interexchange Carrier) and dial around with another carrier works (at the time the proble is occurring), then you can call your PIC and demand they take care of it since you know the problem is theirs.
Unlike the orginal intent to allow easy acess to different carriers, most carriers charge a premium for dial around users, so it shouldn't be used as a substitute for demanding a carrier fix problems (assuming they are long standing problems).
Three that are worth trying for troubleshooting are:
1010222 = MCI (original MCI network, not the Worldcom net)
1010333 = Sprint
1010288 = AT&T
You would dial 101XXXX 1 + 10 digits or for international:
101XXXX 011 + country code + number.
If you get the same result with all three then it isn't the LD carrier.
On the other hand, there is a class of carriers that ONLY offer accesss through manual dial around (for example 1010321.
To verify your current PIC, dial 1 700-555-4141 and listen for an announcment (e.g "thank you for choosing xyz").
Good luck.
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